dsconfig-wrapper

This is a small Python library to complement MAX IV's excellent dsconfig library, which can make the database for the Tango controls system declarative by updating it from a JSON file.

Usually, it looks like this:

flowchart TD
    DatabaseDs[(Tango Database)]
    DatabaseDs -->|dsconfig.dump| JsonFile[JSON file]
    Human -->|vim/emacs| JsonFile
    JsonFile -->|json2tango| DatabaseDs

With this tool, it looks like this:

flowchart TD
    DatabaseDs[(Tango Database)]
    Human -->|vim/emacs| PythonFile[Python file]
    DsconfigWrapper[dsconfig-wrapper] -->|import| PythonFile
    PythonFile -->|dsconfig-wrapper| JsonFile
    JsonFile -->|json2tango| DatabaseDs

This way, we can have our configuration not in JSON, but in Python! And in Python, we can have, for instance, argparse, to create a little program that can generate a configuration with parameters. You can also use Python DRY elements in your configuration (say, you have the same motor, but with various different properties set).

Usage

Just do

pip install dsconfig-wrapper

and then use it to create a config JSON. Example:

test_servers = [
    Server(
        instance_name="my_instance_name",
        class_name="my_class_name",
        devices=[
            Device(
                identifier=Identifier(
                    domain="my_domain",
                    family="my_family",
                    member="my_member",
                    host="my_host:10000",
                ),
                properties={
                    "prop_str": "strvalue",
                    "prop_list_str": ["value1", "value2"],
                    "prop_list_int": [2000, 3000],
                    "prop_int": 2000,
                },
                polled_commands={"update": 1000},
                attribute_properties={
                    "State": AttributeProperties(archive_period_ms=1001),
                    "velocity_mm_per_s": AttributeProperties(
                        archive_abs_change=(-0.5, 0.5),
                        archive_period_ms=5000,
                        rel_change=(-0.05, 0.05),
                    ),
                },
            )
        ],
    )
]
test_config = Config(servers=test_servers)
print(config_to_json(test_config))

Here, we create a config for a device server with class my_class_name and one instance running at tango://myhost:10000/my_domain/my_family/my_member. The update command is polled every second, and we also set some properties and attribute properties.

We now run this program (say it's stored in main.py) and pipe it into dsconfig:

python main.py | json2tango

Voila!